Madison didn’t have an easy childhood. As a kid, her house was always in disrepair. Her parents couldn’t consistently afford electricity or indoor plumbing, never mind fancy appliances and wall hangings. Madison’s classmates made fun of her shabby surroundings. Some refused to play with her.

Even after graduating from college, marrying and settling into a middle-class life, Madison couldn’t shake her insecurity about her home. She read design magazines and blogs obsessively, poring over the latest trends in closet organization and wall colors. She redecorated frequently and was rarely confident in her choices. When she redid her kitchen, she considered more than 200 faucets.

Her husband, Evan, hated how much Madison (their names, like all names in this piece, have been changed as a condition for my interviews) spent on furniture and gadgets they didn’t need. He couldn’t understand her fixation. Why would he? Evan grew up with middle-class parents, in the kind of house Madison was so desperate to re-create.

Studies show that couples argue more about money than about sex, chores or spending time together. For partners who marry across class lines, however, money isn’t just something to fight about. In researching my book about inter-class couples, I found that the financial stability of the spouses’ childhoods shaped their marriages in many ways, contributing to clashes about leisure time, home maintenance and even how to talk through their feelings. These pairs were middle class by the time I met them, but their different backgrounds still caused problems.

For example, Danielle grew up in a working-class family. She dropped out of high school and left her home town, marrying a man she’d later call a lunatic. Over the next six years, she moved 17 times, stood in countless welfare lines and even thought about stealing toilet paper. To cope with this crushing poverty, she “just pretended like [money] didn’t exist,” she told me. “I would just spend what I needed to and never think about it. I was afraid to face the realities of it, which is that it’s limited.”

Then she met her second husband, Jim, whose boss joked that he had grown up with a silver spoon in his mouth. It was true — Jim was raised in a mansion and attended a prestigious university. Though Jim and Danielle have been married for almost 30 years, they still treat money very differently. Danielle, like many of the spouses who grew up working class, didn’t like to budget or develop a long-term savings plan.

Jim, who’d grown up with a financial safety net, wanted the same for his family. He managed his money carefully, always aware of how much was being spent on what. He would pore over coupons and spend hours researching purchases; Danielle would get annoyed with his constant drive to “save 11 cents.” Jim so routinely returned items Danielle bought that she once deliberately spilled soda on their couch so he couldn’t take it back. Another time, she lied and told him stores would not accept returned cologne.

I saw this divide — between planning and going with the flow — flare up in other ways, too. One pair, Scott and Gina, fought bitterly over how to spend their free time. They even briefly broke up over it. This tension affected how they raised their young children. Scott, who grew up in the middle class, believed that their 6- and 3-year-olds should be enrolled in Chinese lessons and pottery classes, and that their free time should be spent watching cooking shows. Gina, who grew up in a working-class family, disagreed. She thought the kids should play freely at home.

Sometimes, talking through these issues presented its own obstacles, which defy stereotypes about how men and women talk to each other. William, for example, was the son of a sawmill repairman and a saleswoman. In his blue-collar family, keeping your feelings to yourself was “dishonest,” a common sentiment among the working-class families I spoke with. He learned to express himself freely (and often loudly). William’s wife, Anneka, grew up in a professional, white-collar community. She learned what many middle-class children do: that reactions should be intellectualized, not expressed in emotional tones. “My knee-jerk reaction to things is to shut up,” Anneka said. “I go underground, back off, think about the situation, and then I’ll come back and react to it.”

Anneka and William had to get used to each other’s emotional styles — ones that may have made sense in the classes from which each spouse came but that initially made less sense to each other. They also learned from each other: William to wait to express his emotions, Anneka to be more willing to feel and express hers. “I am a lot more openly affectionate than I would have been otherwise,” she said.

Another source of tension for inter-class couples is housework. One man I spoke with, Jason, grew up working-class. It took his parents five years to replace their kitchen cabinet doors and more than a decade to save enough to change the linoleum floor. Jason married Lori, a woman who grew up with three beautiful homes and a yacht. Both Jason and Lori had good jobs, and eventually they bought their own large house.

But Jason didn’t adapt easily to their new home. “He would say, ‘I haven’t done anything to deserve this house,’ ” Lori explained. “He doesn’t even in his deep psychology see the house as being his.” Like other working-class spouses I spoke with, he refused to do simple household chores, afraid that he did not have the know-how to care for this “extravagant” new space. At times, he even neglected maintenance on purpose, leaving the mailbox askew after it fell to show his neighbors that he didn’t share their values or fit neatly into their world. Lori found these attitudes infuriating, although she understood where they came from.

Though it shaped these couples’ lives, most people I spoke with swore they never thought about the class differences in their relationships, afraid that doing so made them, in the words of one source, “snotty.” Another man, Jim, denied that class influenced his marriage: “We don’t have a great sense that one person is better than the other person, more privileged or anything like that,” he said. “Class doesn’t make a damned difference.”

Of course, it does. But that’s not necessarily a bad thing. Many of the couples I got to know drew strength from their difference. It’s what brought them together in the first place. Those who grew up poor often disliked the unpredictability of their lives. They were drawn to their middle-class partners because they offered the promise of a stable future. Similarly, those who grew up in the middle class spent their childhoods engaged in many organized, planned activities. They appreciated the unscheduled family time that was more familiar to their partners.

Today, the opportunity to marry — or even meet — someone of a different class is disappearing. Economic segregation is rising in the United States, and inter-class marriages are becoming more rare. The couples I spoke with, though, offer some hope that these differences can be navigated and that even in profoundly unequal times, love can cross class lines.